This Article 
 Bibliographic References 
 Add to: 
The FLOWLENS: A Focus-and-Context Visualization Approach for Exploration of Blood Flow in Cerebral Aneurysms
Dec. 2011 (vol. 17 no. 12)
pp. 2183-2192
Rocco Gasteiger, Department of Simulation and Graphics, University of Magdeburg, Germany
Mathias Neugebauer, Department of Simulation and Graphics, University of Magdeburg, Germany
Oliver Beuing, Department of Neuroradiology, University Hospital Magdeburg, Germany
Bernhard Preim, Department of Simulation and Graphics, University of Magdeburg, Germany
Blood flow and derived data are essential to investigate the initiation and progression of cerebral aneurysms as well as their risk of rupture. An effective visual exploration of several hemodynamic attributes like the wall shear stress (WSS) and the inflow jet is necessary to understand the hemodynamics. Moreover, the correlation between focus-and-context attributes is of particular interest. An expressive visualization of these attributes and anatomic information requires appropriate visualization techniques to minimize visual clutter and occlusions. We present the FLOWLENS as a focus-and-context approach that addresses these requirements. We group relevant hemodynamic attributes to pairs of focus-and-context attributes and assign them to different anatomic scopes. For each scope, we propose several FLOWLENS visualization templates to provide a flexible visual filtering of the involved hemodynamic pairs. A template consists of the visualization of the focus attribute and the additional depiction of the context attribute inside the lens. Furthermore, the FLOWLENS supports local probing and the exploration of attribute changes over time. The FLOWLENS minimizes visual cluttering, occlusions, and provides a flexible exploration of a region of interest. We have applied our approach to seven representative datasets, including steady and unsteady flow data from CFD simulations and 4D PC-MRI measurements. Informal user interviews with three domain experts confirm the usefulness of our approach.

[1] N. Andaluz and M. Zuccarello, Recent Trends in the Treatment of Cerebral Aneurysms: Analysis of a Nationwide Inpatient Database. Neuro-surgery: Pediatrics, 108 (6): 1163–1169, 2008.
[2] S. Appanaboyina, F. Mut, R. Löhner, C. Putman, and J. Cebral, Computational Fluid Dynamics of Stented Intracranial Aneurysms Using Adaptive Embedded Unstructured Grids. Numerical Methods in Fluids, 57 (5): 475– 493, 2008.
[3] L. Augsburger, P. Reymond, E. Fonck, Z. Kulcsar, M. Farhat, M. Ohta, N. Stergiopulos, and D. Rüfenacht, Methodologies to Assess Blood Flow in Cerebral Aneurysms: Current State of Research and Perspectives. Neu-roradiology, 36 (5): 270–277, 2009.
[4] E. A. Bier, M. C. Stone, K. Pier, W. Buxton, and T. D. De Rose., Tool-glass and Magic Lenses: The See-Through Interface. In Proceedings of SIGGRAPH, pages 73–80, 1993.
[5] S. Born, A. Wiebel, J. Friedrich, G. Scheuermann, and D. Bartz, Illustrative Stream Surfaces. IEEE Transactions on Visualization and Computer Graphics, 16 (6): 1329–1338, 2010.
[6] L. Boussel, V. Rayz, A. Martin, G. Acevedo-Bolton, M. T. Lawton, R. Hi-gashida, W. S. Smith, W. L. Young, and D. Saloner, Phase-Contrast Magnetic Resonance Imaging Measurements in Intracranial Aneurysms In Vivo of Flow Patterns, Velocity Fields, and Wall Shear Stress: Comparison with Computational Fluid Dynamics. Magnetic Resonance Imaging in Medicine, 61: 409–417, 2009.
[7] R. D. Brown, J. Huston, R. Hornung, T. Foroud, D. F. Kallmes, D. Klein-dorfer, I. Meissner, D. Woo, L. Sauerbeck, and J. Broderick, Screening for Brain Aneurysm in the Familial Intracranial Aneurysm Study: Frequency and Predictors of Lesion Detection. Neurosurgery: Pediatrics, 108 (6): 1132–1138, 2008.
[8] R. Bürger and H. Hauser, Visualization of Multi-Variate Scientific Data. In Proceedings of EuroVis, pages 117–134, 2007.
[9] J. R. Cebral, M. A. Castro, J. E. Burgess, R. S. Pergolizzi, M. J. Sheridan, and C. M. Putman, Characterization of Cerebral Aneurysms for Assessing Risk of Rupture by Using Patient-Specific Computational Hemo-dynamics Models. American Journal of Neuroradiology, 26 (10): 2550– 2559, 2005.
[10] J. R. Cebral, F. Mut, J. Weir, and C. M. Putman, Association of Hemody-namic Characteristics and Cerebral Aneurysm Rupture. American Journal of Neuroradiology, 32 (2): 264–270, 2011.
[11] J. R. Cebral, F. Mut, J. Weir, and C. M. Putman, Quantitative Characterization of the Hemodynamic Environment in Ruptured and Unruptured Brain Aneurysms. American Journal of Neuroradiology, 32 (1): 145–151, 2011.
[12] I. Chatziprodromou, V. D. Butty, V. B. Makhijani, D. Poulikakos, and Y. Ventikos, Pulsatile Blood Flow in Anatomically Accurate Vessels with Multiple Aneurysms: A Medical Intervention Planning Application of Computational Hemodynamics. Flow, Turbulence and Combustion, 71 (1): 333–346, 2003.
[13] A. Cockburn, A. Karlson, and B. B. Bederson, A Review of Overview+Detail, Zooming, and Focus+Context Interfaces. Computing Surveys, 41:2:1–2:31, 2009.
[14] M. H. Everts, H. Bekker, J. B. Roerdink, and T. Isenberg, Depth-Dependent Halos: Illustrative Rendering of Dense Line Data. IEEE Transactions on Visualization and Computer Graphics, 15 (6): 1299– 1306, 2009.
[15] R. Gasteiger, M. Neugebauer, C. Kubisch, and B. Preim, Adapted Surface Visualization of Cerebral Aneurysms with Embedded Blood Flow Information. In Proceedings of VCBM, pages 25–32, 2010.
[16] A. Hennemuth, O. Friman, C. Schumann, J. Bock, J. Drexl, M. Markl, and H.-O. Peitgen, Fast Interactive Exploration of 4D MRI Flow Data. In Proceedings of SPIE Medical Imaging, 2011.
[17] Y. Hoi, S. H. Woodward, M. Kim, D. B. Taulbee, and H. Meng, Validation of CFD Simulations of Cerebral Aneurysms with Implication of Geometric Variations. Biomechanical Engineering, 128: 844–851, 2006.
[18] S. Juvela, M. Porras, and K. Poussa, Natural History of Unruptured Intracranial Aneurysms: Probability of and Risk Factors for Aneurysm Rupture. Neurosurgery, 93 (3): 379–387, 2000.
[19] J. Krüger, J. Schneider, and R. Westermann, Clearview: An Interactive Context Preserving Hotspot Visualization Technique. IEEE Transactions on Visualization and Computer Graphics, 12 (5): 941–948, 2006.
[20] D. H. Laidlaw, R. M. Kirby, C. D. Jackson, J. S. Davidson, T. S. Miller, M. da Silva, W. H. Warren, and M. J. Tarr, Comparing 2D Vector Field Visualization Methods: A User Study. IEEE Transactions on Visualization and Computer Graphics, 11 (1): 59–70, 2005.
[21] R. S. Laramee, H. Hauser, H. Doleisch, B. Vrolijk, F. H. Post, and D. Weiskopf, The State of the Art in Flow Visualization: Dense and Texture-Based Techniques. Computer Graphics Forum, 23 (2): 203–222, 2004.
[22] D. Lesage, E. D. Angelini, I. Bloch, and G. Funka-Lea, A Review of 3D Vessel Lumen Segmentation Techniques: Models, Features and Extraction Schemes. Medical Image Analysis, 13 (6): 819–845, December 2009.
[23] M. Markl, A. Harloff, T. A. Bley, M. Zaitsev, B. Jung, E. Weigang, M. Langer, J. Hennig, and A. Frydrychowicz, Time-Resolved 3D MR Velocity Mapping at 3T: Improved Navigator-Gated Assessment of Vascular Anatomy and Blood Flow. Magnetic Resonance Imaging, 25 (4): 824– 831, 2007.
[24] O. Mattausch, T. Theußl, H. Hauser, and E. Gröller, Strategies for Interactive Exploration of 3D Flow Using Evenly-Spaced Illuminated Streamlines. In Proceedings of SCCG, pages 230–241, 2003.
[25] J. E. Moore, C. Xu, S. Glagov, C. K. Zarins, and D. N. Ku, Fluid Wall Shear Stress Measurements in a Model of the Human Abdominal Aorta: Oscillatory Behavior and Relationship to Atherosclerosis. Atherosclerosis, 110 (2): 225–240, 1994.
[26] M. Neugebauer, V. Diehl, M. Skalej, and B. Preim, Geometric Reconstruction of the Ostium of Cerebral Aneurysms. In Proceedings of VMV, pages 307–314, 2010.
[27] M. Neugebauer, R. Gasteiger, O. Beuing, and et al. Map Displays for the Analysis of Scalar Data on Cerebral Aneurysm Surfaces. Computer Graphics Forum (EuroVis), 28 (3): 895–902, 2009.
[28] M. Neugebauer, G. Janiga, O. Beuing, M. Skalej, and B. Preim, Anatomy-Guided Exploration of Blood Flow in Cerebral Aneurysms. In Proceedings of EuroVis, pages 1041–1050, 2011.
[29] P. Neumann, T. Isenberg, and S. Carpendale, NPR Lenses: Interactive Tools for Non-Photorealistic Line Drawings. In Proceedings of Smart Graphics, pages 10–22. Springer, 2007.
[30] A. M. Nixon, M. Gunel, and B. E. Sumpio, The Critical Role of Hemody-namics in the Development of Cerebral Vascular Disease. Neurosurgery, 112 (6): 1240–1253, 2010.
[31] T. Salzbrunn, H. Jänicke, T. Wischgoll, and G. Scheuermann, The State of the Art in Flow Visualization: Partition-Based Techniques. In Proceedings of SimVis, pages 75–92, 2008.
[32] R. Schmidt, K. Singh, and R. Balakrishnan, Sketching and Composing Widgets for 3D Manipulation. Computer Graphics Forum, 27 (2): 301– 310, 2008.
[33] J. Schöberl, NETGEN An Advancing Front 2D/3D-Mesh Generator Based on Abstract Rules. Computing and Visualization in Science, 1: 41– 52, 1997.
[34] D. M. Sforza, C. M. Putman, and J. R. Cebral, Hemodynamics of Cerebral Aneurysms. Annual Review of Fluid Mechanics, 41: 91–107, 2009.
[35] S. Tateshima, A. Chien, J. Sayre, J. R. Cebral, and F. Viuela, The Effect of Aneurysm Geometry on the Intra-Aneurysmal Flow Condition. Neu-roradiology, 52 (12): 1135–1141, 2010. Published online.
[36] D. J. Tritton, Physical Fluid Dynamics. Clarendon Press, 1988.
[37] R. van Pelt, J. O. Bescós, M. Breeuwer, R. E. Clough, and E. Gröller, Exploration of 4D MRI Blood-Flow Using Stylistic Visualization. IEEE Transactions on Visualization and Computer Graphics, 16 (6): 1339– 1347, 2010.
[38] J. Viega, M. J. Conway, G. Williams, and R. Pausch, 3D Magic Lenses. In Proceedings of UIST, pages 51–58, 1996.
[39] I. Viola and E. Gröller., Smart Visibility in Visualization. In Proceedings of Computational Aesthetics, pages 209–216, 2005.
[40] I. Viola, A. Kanitsar, and M. E. Gröller, Importance-Driven Feature Enhancement in Volume Visualization. IEEE Transactions on Visualization and Computer Graphics, 11 (4): 408–.418, 2005.
[41] L. Wang, Y. Zhao, K. Mueller, and A. E. Kaufman, The Magic Volume Lens: An Interactive Focus+Context Technique for Volume Rendering. In Proceedings of IEEE Visualization, pages 367–374, 2005.

Index Terms:
Flow Visualization, Focus-and-Context, Illustrative Rendering, Aneurysm.
Rocco Gasteiger, Mathias Neugebauer, Oliver Beuing, Bernhard Preim, "The FLOWLENS: A Focus-and-Context Visualization Approach for Exploration of Blood Flow in Cerebral Aneurysms," IEEE Transactions on Visualization and Computer Graphics, vol. 17, no. 12, pp. 2183-2192, Dec. 2011, doi:10.1109/TVCG.2011.243
Usage of this product signifies your acceptance of the Terms of Use.